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United States Patent | 5,133,387 |
Pietrykowski ,   et al. | July 28, 1992 |
A bellows is comprised of a unitary body formed of relatively thin annular walls, open at one end and closed at the other. The walls are constructed and arranged as a spiral groove, whereby the bellows can be fabricated from plastic by injection molding in a relatively inexpensive fashion. The bellows can be formed of two layers joined to one another, a backup layer formed of metal or plastic and a protective layer formed of plastic such as PFA and PVDF.
Inventors: | Pietrykowski; Gabriel J. (Bryan, OH); White; Lawrence W. (Bryan, OH) |
Assignee: | The Aro Corporation (Bryan, OH) |
Appl. No.: | 585407 |
Filed: | September 20, 1990 |
Current U.S. Class: | 138/30; 138/26; 220/721 |
Intern'l Class: | F16L 055/04 |
Field of Search: | 138/26,30,31,121,122,173,DIG. 10 220/85 B 417/540 383/120 |
2360590 | Oct., 1944 | Schweller | 138/30. |
2899110 | Aug., 1959 | Parker | 220/85. |
2918090 | Dec., 1959 | Shelly | 138/30. |
3061039 | Oct., 1962 | Peters | 138/30. |
3099189 | Jul., 1963 | Blondiau | 138/30. |
3230975 | Jan., 1966 | Mercier | 138/30. |
3273577 | Sep., 1966 | Moore | 138/30. |
3422853 | Jan., 1969 | Schmid | 138/30. |
3474844 | Oct., 1969 | Lindstrom et al. | 383/120. |
3862646 | Jan., 1975 | Tarsha | 138/31. |
3865270 | Feb., 1975 | Petersson | 220/85. |
3939872 | Feb., 1976 | Wentworth | 138/31. |
4691739 | Sep., 1987 | Gooden | 138/31. |
4777982 | Oct., 1988 | Borowitz et al. | 138/30. |
4911204 | Mar., 1990 | Martin | 138/30. |
Foreign Patent Documents | |||
1389226 | Jan., 1965 | FR | 220/85. |
1030901 | Feb., 1989 | JP | 138/30. |